Inbred corn line PHMKO

ABSTRACT

According to the invention, there is provided an inbred corn line, designated PHMK0. This invention thus relates to the plants and seeds of inbred corn line PHMK0 and to methods for producing a corn plant produced by crossing the inbred line PHMK0 with itself or with another corn plant. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHMK0 with another corn line or plant.

FIELD OF THE INVENTION

This invention is in the field of corn breeding, specifically relating to an inbred corn line designated PHMK0.

BACKGROUND OF THE INVENTION Plant Breeding

Field crops are bred through techniques that take advantage of the plant's method of pollination. A plant is self-pollinated if pollen from one flower is transferred to the same or another flower- of the same plant. A plant is cross-pollinated if the pollen comes from a flower on a different plant.

Corn plants (Zea maysL.) can be bred by both self-pollination and cross-pollination techniques. Corn has separate male and female flowers on the same plant, located on the tassel and the ear, respectively. Natural pollination occurs in corn when wind blows pollen from the tassels to the silks that protrude from the tops of the incipient ears.

The development of a hybrid corn variety involves three steps: (1) the selection of plants from various germplasm pools; (2) the selfing of the selected plants for several generation to produce a series of inbred lines, which, although different from each other, breed true and are highly uniform; and (3) crossing the selected inbred lines with unrelated inbred lines to produce the hybrid progeny (F₁). During the inbreeding process in corn, the vigor of the lines decreases. Vigor is restored when two unrelated inbred lines are crossed to produce the hybrid progeny. An important consequence of the homozygosity and homogeneity of the inbred lines is that the hybrid between any two inbreds will always be the same. Once the inbreds that give a superior hybrid have been identified, the hybrid seed can be reproduced indefinitely as long as the homogeneity of the inbred parents is maintained.

The objective of commercial maize inbred line development programs is to develop new inbred lines that combine to produce high grain yields and superior agronomic performance in hybrid combination. The primary trait breeders seek is yield. However, other major agronomic traits are of importance in hybrid combination and have an impact on yield or otherwise provide superior performance in hybrid combinations. Such traits include percent grain moisture at harvest, relative maturity, resistance to stalk breakage, resistance to root lodging, grain quality, and disease and insect resistance. In addition the lines per se must have acceptable performance for parental traits such as seed yields, kernel sizes, pollen production, all of which affect ability to provide parental lines in sufficient quantity and quality for hybridization. Traits have been shown to be under genetic control and many if not all of the traits are affected by multiple genes. Thus, to be selected as an inbred line, the inbred must be able to combine such that the desired traits are passed to the hybrid and also be able to satisfy production requirements as a parental line.

Pedigree Breeding

The pedigree method of breeding is the mostly widely used methodology for new inbred line development.

In general terms this procedure consists of crossing two inbred lines to produce the non-segregating F₁ generation, and self pollination of the F₁ generation to produce the F₂ generation that segregates for all factors for which the inbred parents differ. An example of this process is set forth below. Variations of this generalized pedigree method are used, but all these variations produce a segregating generation which contains a range of variation for the traits of interest.

Example 1. Hypothetical example of pedigree breeding program

Consider a cross between two inbred lines that differ for alleles at five loci. The parental genotypes are:

    ______________________________________                                         Parent 1                                                                               A      b     C   d   e   F/A  b   C   d   e   F                        Parent 2                                                                               a      B     c   D   E   f/a  B   c   D   E   f                        ______________________________________                                    

the F₁ from a cross between these two parents is:

    ______________________________________                                         F.sub.1  A b C d e F/a B c D E f                                               ______________________________________                                    

Selfing F₁ will produce an F₂ generation with the following genotypes:

    ______________________________________                                         A    B      c      D   E    f/a  b    C   d    e    F                          A    B      c      D   e    f/a  b    C   d    E    F                          A    B      c      D   e    f/a  b    C   d    e    F                          .                                                                              .                                                                              ______________________________________                                    

The number of genotypes in the F₂ is 3⁶ for six segregating loci (729) and will produce (2⁶)-2 possible new inbreds, (62 for six segregating loci).

Each inbred parent which is used in breeding crosses represents a unique combination of genes, and the combined effects of the genes define the performance of the inbred and its performance in hybrid combination. There is published evidence (Smith, O. S., J. S. C. Smith, S. L. Bowen, R. A. Tenborg and S. J. Wall, TAG 80:833-840 (1990)) that each of these lines are different and can be uniquely identified on the basis of genetically-controlled molecular markers.

It has been shown (Hallauer, Arnel R. and Miranda, J. B. Fo. Quantitative Genetics in Maize Breeding, Iowa State University Press, Ames Iowa (1981)) that most traits of economic value in maize are under the genetic control of multiple genetic loci, and that there are a large number of unique combinations of these genes present in elite maize germplasm. If not, genetic progress using elite inbred lines would no longer be possible. Studies by Duvick and Russell (Duvick, D. N. Maydica 37:69-79 (1992); Russell, W. A. Maydica XXIX:375-390 (1983)) have shown that over the last 50 years the rate of genetic progress in commercial hybrids has been between 1 and 2% per year.

The number of genes affecting the trait of primary economic importance in maize, grain yield, has been estimated to be in the range of 10-1000. Inbred lines which are used as parents for breeding crosses differ in the number and combination of these genes. These factors make the plant breeder's task more difficult. Compounding this is evidence that no one line contains the favorable allele at all loci, and that different alleles have different economic values depending on the genetic background and field environment in which the hybrid is grown. Fifty years of breeding experience shows that there are many genes affecting grain yield and each of these has a relatively small effect on this trait. The effects are small compared to breeders' ability to measure grain yield differences in evaluation trials. Therefore, the parents of the breeding cross must differ at several of these loci so that the genetic differences in the progeny will be large enough that breeders can develop a line that increases the economic worth of its hybrids over that of hybrids made with either parent.

If the number of loci segregating in a cross between two inbred lines is n, the number of unique genotypes in the F₂ generation is 3^(n) (Table 2) and the number of unique inbred lines from this cross is {(2^(n)) -2}. Only a very limited number of these combinations are useful. Only about 1 in 10,000 of the progeny from F₂ 's are commercially useful.

By way of example, if it is assumed that the number of segregating loci in F₂ is somewhere between 20 and 50, and that each parent is fixed for half the favorable alleles, it is then possible to calculate approximate probabilities of finding an inbred that has the favorable allele at {(n/2)+m} loci, where n/2 is the number of favorable alleles in each of the parents and m is the number of additional favorable alleles in the new inbred. See Example 2 below. The number m is assumed to be greater than three because each allele has so small an effect that evaluation techniques are not sensitive enough to detect differences due to three or less favorable alleles. The probabilities in Example 2 are on the order of 10⁻⁵ or smaller and they are the probabilities that at least one genotype with (n/2)+m favorable alleles will exist.

To put this in perspective the number of plants grown on 60 million acres (approximate US corn acreage) at 25,000 plants/acre is 1.5×10¹².

Example 2. Probability of finding an inbred with m of n favorable alleles.

Assume each parent has n/2 of the favorable alleles and only 1/2 of the combinations of loci are economically useful.

    ______________________________________                                         no. of  no. favorable                                                                              no. additional                                                                              Probability                                   segregating                                                                            alleles in  favorable alleles                                                                           that genotype                                 loci (n)                                                                               Parents (n/2)                                                                              in new inbred                                                                               occurs*                                       ______________________________________                                         20      10          14           3 × 10.sup.-5                           24      12          16           2 × 10.sup.-5                           28      14          18           1 × 10.sup.-5                           32      16          20           8 × 10.sup.-6                           36      18          22           5 × 10.sup.-6                           40      20          24           3 × 10.sup.-6                           44      22          26           2 × 10.sup.-6                           48      24          28           1 × 10.sup.-6                           ______________________________________                                          *Probability that a useful combination exists, does not include the            probability of identifying this combination if it does exist.            

The possibility of having a usably high probability of actually being able to identify this genotype based on replicated field testing would be most likely smaller than this, and is a function of how large a population of genotypes is tested and how testing resources are allocated in the testing program.

At Pioneer Hi-Bred International, a typical corn research station has a staff of four, and 20 acres of breeding nursery. Those researchers plant those 20 acres with 25,000 nursery rows, 15,000 yield test plots in 10-15 yield test sites, and one or two disease-screening nurseries. Employing a temporary crew of 20 to 30 pollinators, the station makes about 65,000 hand pollinations per growing season. Thus, one of the largest plant breeding programs in the world does not have a sufficiently large breeding population to be able to rely upon "playing the numbers" to obtain successful research results. Nevertheless, Pioneer's breeders at each station produce from three to ten new inbreds which are proposed for commercial use each year. Over the 32 Pioneer research stations in North America, this amounts to from about 100 to 300 new inbreds proposed for use, and less than 50 and more commonly less than 30 of these inbreds that actually satisfy the performance criteria for commercial use.

This is a result of plant breeders using their skills, experience, and intuitive ability to select inbreds having the necessary qualities.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred corn line, designated PHMK0 . This invention thus relates to the seeds of inbred corn line PHMK0, to the plants of inbred corn line PHMK0, and to methods for producing a corn plant produced by crossing the inbred line PHMK0 with itself or another corn line. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line PHMK0 with another corn line.

DEFINITIONS

In the description and examples that follow, a number of terms are used herein. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided. ABS is in absolute terms and % MN is percent of the mean for the experiments in which the inbred or hybrid was grown.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were not barren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near the time of pollination, and is an indication of whether a hybrid or inbred would snap or break near the time of flowering under severe winds. Data are presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Actual yield of the grain at harvest in bushels per acre adjusted to 15.5% moisture.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plot and represents the percentage of plants that did not drop ears prior to harvest.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to the highest placed developed ear node attachment and is measured in inches.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher the rating the larger the ear size.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishment in the spring and represents the number of plants that emerge on a per plot basis for the inbred or hybrid.

GDU SHD=GDU TO SHED. The number of growing degree units (GDUs) or heat units required for an inbred line or hybrid to have approximately 50 percent of the plants shedding pollen and is measured from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimum temperature used is 50° F. For each inbred or hybrid it takes a certain number of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for an inbred line or hybrid to have approximately 50 percent of the plants with silk emergence from time of planting. Growing degree units are calculated by the Barger Method as given in GDU SHD definition.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the general appearance of the shelled grain as it is harvested based on such factors as the color of the harvested grain, any mold on the grain, and any cracked grain. High scores indicate good grain quality.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture of the grain at harvest.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant from the ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount of pollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tassels collected as shedding commences minus dry weight from similar tassels harvested after shedding is complete.

It should be understood that the inbred can, through routine manipulation of cytoplasmic factors, be produced in a cytoplasmic male-sterile form which is otherwise phenotypically identical to the male-fertile form.

PRM=PREDICTED RM. This trait, predicted relative maturity (RM), is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes standard linear regression analyses and is referred to as the Comparative Relative Maturity Rating System which is similar to the Minnesota Relative Maturity Rating System.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that do not root lodge; plants that lean from the vertical axis at an approximately 30° angle or greater would be counted as root lodged.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount of scatter grain (lack of pollination or kernel abortion) on the ear. The higher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amount of vegetative growth after emergence at the seedling stage (approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX. The selection index gives a single measure of the hybrid's worth based on information for up to five traits. A corn breeder may utilize his or her own set of traits for the selection index. One of the traits that is almost always included is yield. The selection index data presented in the tables represent the mean value averaged across testing stations.

STA GRN=STAY GREEN. Stay green is the measure of plant health near the time of black layer formation (physiological maturity). A high score indicates better late-season plant health.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plants per plot.

STK LDG=STALK LODGING. This is the percentage of plants that did not stalk lodge (stalk breakage) as measured by either natural lodging or pushing the stalks and determining the percentage of plants that break below the ear.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure the degree of blasting (necrosis due to heat stress) of the tassel at time of flowering. A 1 would indicate a very high level of blasting at time of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate the relative size of the tassel. The higher the rating the larger the tassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams) just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate the relative hardness (smoothness of crown) of mature grain. A 1 would be very soft (extreme dent) while a 9 would be very hard (flinty or very smooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that could possibly shed pollen was taken. Data is given as percentage of tillers: number of tillers per plot divided by number of plants per plot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grain in pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain in pounds for a given volume (bushel) adjusted for percent moisture.

YLD=YIELD. It is the same as BU ACR ABS.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relative rating for yield based on plot ear piles. The higher the rating the greater visual yield appearance.

MDM CPX=Maize Dwarf Mosaic Complex (MDMV=Maize Dwarf Mosaic Virus & MCDV=Maize Chlorotic Dwarf Virus): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

SLF BLT=Southern Leaf Blight (Bipolaris maydis, Helminthosporium maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

NLF BLT=Northern Leaf Blight (Exserohilum turcicum, H. turcicum): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant .

COM RST=Common Rust (Puccinia sorghi): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

STW WLT=Stewart's Wilt (Erwinia stewartii): Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant.

HD SMT=Head Smut (Sphacelotheca reiliana): Percentage of plants that did not have infection.

EAR MLD=General Ear Mold: Visual rating (1-9 score) where a "1" is very susceptible and a "9" is very resistant. This is based on overall rating for ear mold of mature ears without determining specific mold organism, and may not be predictive for a specific ear mold.

ECB DPE=Dropped ears due to European Corn Borer (Ostrinia nubilalis): Percentage of plants that did not drop ears under second brood corn borer infestation. ECB 2SC=European Corn Borer Second Brood (Ostrinia nubilalis): Visual rating (1-9 score) of post flowering damage due to infestation by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

ECB 1LF=European Corn Borer First Brood (Ostrinia nubilalis): Visual rating (1-9 score) of pre-flowering leaf feeding by European Corn Borer. A "1" is very susceptible and a "9" is very resistant.

DETAILED DESCRIPTION OF THE INVENTION

Inbred corn line PHMK0 is a yellow, dent corn inbred that provides an acceptable female parental line in crosses for producing first generation F₁ corn hybrids. PHMK0 is best adapted to the Southeast region of the United States. PHMK0 has exceptional gray leaf spot resistance and appears to contribute this trait in hybrid combination, and to much of the progeny in breeding populations as well. Hybrids containing PHMK0 appear to have exceptional performance under high heat, particularly high night time heat conditions characteristic of the Southern Corn Belt. Gray leaf resistance is in demand by farmers and this inbred clearly distinguishes this trait in hybrids. In addition, it offers exceptional yield and stress tolerance. Unique to this inbred is its yield potential coupled with gray leaf spot resistance, both in inbred per se test and in hybrid combinations. In hybrid combination, PHMK0 also seems to produce hybrids with high ear placement.

The inbred has shown uniformity and stability within the limits of environmental influence for all the traits as described in the Variety Description Information (Table 1) that follows. Most of the data in the Variety Description information was collected at Johnston, Iowa. The inbred has been self-pollinated and ear-rowed a sufficient number of generations with careful attention paid to uniformity of plant type to ensure homozygosity and phenotypic stability. The line has been increased both by hand and in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in PHMK0.

Inbred corn line PHMK0, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resulting corn plants under self-pollinating or sib-pollinating conditions with adequate isolation, and harvesting the resulting seed, using techniques familiar to the agricultural arts.

                  TABLE 1                                                          ______________________________________                                         VARIETY DESCRIPTION INFORMATION                                                INBRED = PHMKO                                                                 Type: Dent   Region Best Adapted: SOUTHEAST                                    ______________________________________                                         A.  Maturity: Average across maturity zones. Zone: 0                               Heat Unit Shed: 1590                                                           Heat Unit Silk: 1650                                                           No. Reps: 54                                                               HEAT UNITS =                                                                    ##STR1##                                                                      B.  Plant Characteristics:                                                         Plant height (to tassel tip): 228 cm                                           Length of top ear internode: 10 cm                                             Number of ears per stalk: SINGLE                                               Ear height (to base of top ear): 82 cm                                         Number of tillers: NONE                                                        Cytoplasm type: NORMAL                                                     C.  Leaf:                                                                          Color: (WF9) MEDIUM GREEN                                                      Angle from Stalk: <30 degrees                                                  Marginal Waves: (WF9) FEW                                                      Number of Leaves (mature plants): 19                                           Sheath Pubescence: (W22) LIGHT                                                 Longitudinal Creases: (OH56A) FEW                                              Length (Ear node leaf): 76 cm                                                  Width (widest point, ear node leaf): 10 cm                                 D.  Tassel:                                                                        Number lateral branches: 8                                                     Branch Angle from central spike: 30- 40 degrees                                Pollen Shed: medium based on Pollen Yield Test                                 (85% of experiment means)                                                      Peduncle Length (top leaf to basal branches): 25 cm                            Anther Color: YELLOW                                                           Glume Color: GREEN                                                         E.  Ear (Husked Ear Data Except When Stated Otherwise):                            Length: 16 cm                                                                  Weight: 138 gm                                                                 Mid-point Diameter: 41 mm                                                      Silk Color: GREEN                                                              Husk Extension (Harvest stage): LONG                                           (5-10 cm Beyond Ear Tip)                                                       Husk Leaf: SHORT (<8 cm)                                                       Taper of Ear: SLIGHT                                                           Position of Shank (dry husks): UPRIGHT                                         Kernel-Rows: STRAIGHT DISTINCT Number = 17                                     Husk Color (fresh): LIGHT GREEN                                                Husk Color (dry): BUFF                                                         Shank Length: 7 cm                                                             Shank (No. of internodes): 9                                               F.  Kernel (Dried):                                                                Size (from ear mid-point)                                                      Length: 11 mm                                                                  Width: 8 mm                                                                    Thick: 5 mm                                                                    Shape Grade (% rounds): 20-40 (28% medium round based                          on Parent Test Data)                                                           Pericarp Color: COLORLESS                                                      Aleurone Color: HOMOZYGOUS YELLOW                                              Endosperm Color: YELLOW                                                        Endosperm Type: NORMAL STARCH                                                  Gm Wt/100 Seeds (unsized): 30 gm                                           G.  Cob:                                                                           Diameter at mid-point: 22 mm                                                   Strength: STRONG                                                               Color: RED                                                                 H.  Diseases:                                                                      Corn Lethal Necrosis (MCMV = Maize Chlorotic Mottle                            Virus and MDMV = Maize Dwarf Mosaic Virus):                                    INTERMEDIATE                                                                   Maize Dwarf Mosaic Complex (MDMV & MCDV = Maize Dwarf                          Virus): SUSCEPTIBLE                                                            Anthracnose Stalk Rot (C. graminicola): INTERMEDIATE                           S. Leaf Blight (B. maydis): RESISTANT                                          Carbonum Leaf Blight (H. carbonum): HIGHLY                                     RESISTANT                                                                      N. Leaf Blight (E. turcicum): RESISTANT                                        Common Rust (P. sorghi): RESISTANT                                             Sourthern Rust (P. polysora): RESISTANT                                        Gray Leaf Spot (C. zeae): RESISTANT                                            Stewart's Wilt (E. stewartii): HIGHLY RESISTANT                                Common Smut (U. maydis): HIGHLY RESISTANT                                      Head Smut (S. reiliana): HIGHLY RESISTANT                                      Fusarium Ear Mold (F. moniliforme): RESISTANT                              I.  Insects:                                                                       European Corn Borer-1 Leaf Damage                                              (Pre-flowering): SUSCEPTIBLE                                                   European Corn Borer-2 (Post-flowering): INTERMEDIATE                           The above descriptions are based on a scale of 1-9, 1                          being highly susceptible, 9 being highly resistant.                            S (Susceptible): Would generally represent a score of 1-3.                     I (Intermediate): Would generally represent a score                            of 4-5.                                                                        R (Resistant): would generally represent a score of 6-7.                       H (Highly Resistant): Would generally represent a score                        of 8-9. Highly resistant does not imply the inbred is                          immune.                                                                    J.  Variety Most Closely Resembling:                                           Character       Inbred                                                         Maturity        PHK29                                                          Usage           PHK29                                                          PHK29 (PVP Certificate No. 8700214) is a Pioneer Hi-Bred                       International, Inc. proprietary inbred.                                        Data for Items B, C, D, E, F, and G is based primarily on a                    maximum of 4 reps from Johnston, Iowa grown in 1991 and                        1992, plus description information from the maintaining                        station.                                                                       ______________________________________                                          *If maximum is greater than 86 degrees fahrenheit, then 86 is used and if      minimum is less than 50, then 50 is used. Heat units accumulated daily an      can not be less than 0.                                                  

ELECTROPHORESIS RESULTS Isozyme Genotypes for PHMK0

Isozyme data were generated for inbred corn line PHMK0 according to the procedures described in Stuber, C. W., Wendel, J. F., Goodman, M. M., and Smith, J. S. C., "Techniques and Scoring Procedures for Starch Gel Electrophoresis of Enzymes from Maize (Zea mays L.)", Technical Bulletin No. 286, North Carolina Agricultural Research Service, North Carolina State University, Raleigh, NC (1988).

The data in Table 2 compares PHMK0 with its parents, PHK29 and PHME5.

                  TABLE 2                                                          ______________________________________                                         ELECTROPHORESIS RESULTS FOR PHMKO                                              AND ITS PARENTS PHK29 AND PHME5                                                                 PARENTS                                                       LOCI     PHMKO         PHK29   PHME5                                           ______________________________________                                         ACP1     4             4       4                                               ADH1     4             4       4                                               CAT3     9             9       9                                               DIA1     12            12      12                                              GOT1     4             4       4                                               GOT2     4             4       4                                               GOT3     4             4       4                                               IDH1     4             4       4                                               IDH2     4             4       4                                               MDH1     6             6       6                                               MDH2     6               3.5   6                                               MDH3     16            16      16                                              MDH4     12            12      12                                              MDH5     12            12      12                                              MMM      4             4       4                                               PGM1     9             9       9                                               PGM2     4             4       4                                               PGD1     2               3.8   2                                               PGD2     5             5       5                                               PHI1     4             4       4                                               ______________________________________                                    

Examples Inbred and Hybrid Performance of PHMK0

In the examples that follow, the traits and characteristics of inbred corn line PHMK0 are given as a line in comparison with other inbreds and in hybrid combination. The data collected on inbred corn line PHMK0 is presented for the key characteristics and traits.

Table 3A compares PHMK0 to its PHK29 parent. The data shows PHMK0 has lower yield and test weight but higher grain harvest moisture than PHK29. PHMK0 is taller plant with higher ear placement and flowers (GDU Shed and GDU silk) later than PHK29. PHMK0 has better staygreen and resistance to ear mold, northern leaf blight, Stewart's wilt and first and second brood European corn borer.

Table 3B shows PHMK0 is higher yielding with lower grain harvest moisture compared to its PHME5 parent. PHMK0 is taller with higher ear placement and flowers (GDU Shed and GDU Silk) similarly to PHME5.

The results in Table 3C show PHMK0 has lower yield and test weight and higher grain harvest moisture compared to PHW79. PHMK0 flowers (GDU Shed and GDU Silk) later than PHW79.

Table 3D shows PHMK0 has higher yield and grain harvest moisture but lower test weight than PHW52. PHMK0 is taller with higher ear placement and flowers (GDU Shed and GDU Silk) later than PHW52. PHMK0 has better seedling vigor and early stand count than PHW52. PHMK0 has better staygreen as well as better stalk and root lodging resistance compared to PHW52. PHMK0 has better disease and insect resistance than PHW52 as shown by its better resistance to northern leaf blight, Stewart's wilt and first and second European corn borer.

Table 3E compares PHMK0 to PHP38. PHMK0 has higher yield and grain harvest moisture but lower test weight compared to PHP38. PHMK0 is a taller inbred with higher ear placement and flowers (GDU Shed and GDU Silk) later than PHP38. PHMK0 has better resistance to northern leaf blight, Stewart's wilt and first and second brood European corn borer compared to PHP38.

The results in Table 3F show PHMK0 has lower yield and test weight but higher grain harvest moisture than PHP85. PHMK0 is taller with higher ear placement and flowers (GDU Shed and GDU Silk) later than PHP85. PHMK0 has better stalk and root lodging resistance plus shows more resistance to northern leaf blight, Stewart's wilt and first and second brood European corn borer compared to PHP85.

Table 4A compares PHMK0 to PHW52 where both inbreds were crossed to the same inbred testers. The data shows the PHMK0 hybrids have lower yield and test weight but higher grain harvest moisture than the PHW52 hybrids. The PHMK0 hybrids are taller with higher ear placement than the PHW52 hybrids.

Table 4B compares PHMK0 to PHP38 when they were crossed to the same inbred testers. The PHMK0 hybrids have lower yield and test weight and higher grain harvest moisture than the PHP38 hybrids. The PHMK0 hybrids have better staygreen than the PHP38 hybrids which is probably attributed to its tolerance to gray leaf spot.

Table 4C compares PHMK0 to PHP85 when they were crossed to the same inbred testers. The PHMK0 hybrids are lower yielding and have a higher grain harvest moisture compared to the PHP85 hybrids. The PHMK0 hybrids have better staygreen than the PHP85 hybrids. Again, this is attributed to PHMK0's resistance to gray leaf spot. The PHMK0 hybrids are taller with higher ear placement compared to the PHP85 hybrids.

Table 5A compares PHMK0 to PHW52 when both were crossed to the same inbred. The PHMK0 hybrid has lower yield and test weight and higher grain harvest moisture compared to the PHW52 hybrid. The PHMK0 hybrid has better stalk lodging resistance but is more susceptible to root lodging than the PHW52 hybrid. The PHMK0 hybrid has better early stand establishment than the PHW52 hybrid. The PHMK0 hybrid is taller with higher ear placement compared to the PHW52 hybrid.

Table 5B compared PHMK0 to PHW52 when they were crossed to the same inbred, an inbred different from the inbred in Table 5A. The PHMK0 hybrid has lower yield and test weight and higher grain harvest moisture compared to the PHW52 hybrid. The PHMK0 and PHW52 hybrid have similar stalk lodging resistance but the PHMK0 hybrid is significantly more susceptible to root lodging. The PHMK0 hybrid has better staygreen, attributed to its tolerance to gray leaf spot. The PHMK0 hybrid is taller with higher ear placement and sheds later than the PHW52 hybrid.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 compares the yield of PHMK0 and PHW79. Both inbreds have above average yield with PHW79 yielding better in low yield environments compared to PHMK0. PHMK0 and PHW79 have similar yields in high yield environments.

FIG. 2 compares the yield of PHMK0 and PHW52. PHMK0 is higher yielding than PHW52 in both low and high yield environments. PHMK0 has above average yield whereas PHW52 has above average yield only in high yield environments.

FIG. 3 compares the yield of PHMK0 to PHP38. PHMK0 outyields PHP38 both in low and high yield environments. PHMK0 has above average yield whereas PHP38 has a below average yield, both in low and high yield environments.

FIG. 4 compares the yield of PHMK0 to PHP85. The yield of PHMK0 has below average yield compared to PHP85 both, in high and low yield environments.

                                      TABLE 3A                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMKO                                                             VARIETY #2 - PHK29                                                             * = 10% SIG + = 5% SIG # = 1% SIG                                              __________________________________________________________________________                  BU  BU   YLD         EAR  BAR   PLT   EAR   SDG                           VAR  ACR ACR  SC    MST   SZ   PLT   HT    HT    VGR                   DEPT    #    ABS % MN ABS   ABS   ABS  ABS   ABS   ABS   ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1    77.7                                                                               107  5.6   27.2  5.5  87.1  88.4  37.3  5.1                           2    86.6                                                                               121  6.4   21.2  5.5  92.3  85.0  32.4  5.5                           LOCS 16  16   23    24    21   37    47    47    45                            REPS 49  49   25    61    21   60    69    74    60                            DIFF 8.9 14   0.8   6.1   0.0  5.2   3.5   5.0   0.4                           PROB .176                                                                               .163 .044+ .000# .893 .085* .000# .000# .055*                 __________________________________________________________________________                  EST  DRP  TIL   GDU   GDU   POL  TAS  TEX   TST                           VAR  CNT  EAR  LER   SHD   SLK   SC   SZ   EAR   WT                    DEPT    #    ABS  ABS  ABS   ABS   ABS   ABS  ABS  ABS   ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1    33.7 99.1 0.7   1558  1620  5.7  4.8  4.5   54.4                          2    31.6 100.0                                                                               3.0   1483  1501  5.3  5.1  5.3   58.1                          LOCS 70   1    41    56    53    18   29   15    17                            REPS 142  2    55    67    59    21   33   15    51                            DIFF 2.1  0.9  2.3   75    119   0.4  0.3  0.9   3.7                           PROB .003#     .019+ .000# .000# .238 .222 .054* .000#                 __________________________________________________________________________                 GRN SCT   STA   STK RT  EAR NLF   STW   ECB   ECB                          VAR APP GRN   GRN   LDG LDG MLD BLT   WLT   1LF   2SC                  DEPT    #   ABS ABS   ABS   ABS ABS ABS ABS   ABS   ABS   ABS                  __________________________________________________________________________     TOTAL SUM                                                                              1   6.7 5.4   6.5   96.5                                                                               98.9                                                                               7.3 5.7   8.0   5.1   5.9                          2   7.1 6.8   5.5   92.6                                                                               97.1                                                                               8.0 2.9   7.0   4.1   4.2                          LOCS                                                                               8   25    32    14  6   16  10    6     18    7                            REPS                                                                               15  27    54    28  8   18  13    6     20    11                           DIFF                                                                               0.4 1.4   1.0   3.9 1.8 0.7 2.8   1.0   1.0   1.7                          PROB                                                                               .380                                                                               .001# .037+ .297                                                                               .598                                                                               .151                                                                               .000# .041+ .038+ .115                 __________________________________________________________________________

                                      TABLE 3B                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMKO                                                             VARIETY #2 - PHME5                                                             * = 10% SIG + = 5% SIG # = 1% SIG                                              __________________________________________________________________________                 BU  BU       BAR PLT  EAR  SDG                                             VAR ACR ACR MST  PLT HT   HT   VGR                                     DEPT    #   ABS % MN                                                                               ABS  ABS ABS  ABS  ABS                                     __________________________________________________________________________     TOTAL SUM                                                                              1   93.5                                                                               104 35.7 94.3                                                                               100.3                                                                               37.3 5.5                                             2   71.4                                                                               81  39.0 95.7                                                                               84.8 26.9 4.9                                             LOCS                                                                               3   3   3    3   2    2    4                                               REPS                                                                               12  12  12   10  6    7    11                                              DIFF                                                                               22.1                                                                               23  3.3  1.4 15.4 10.3 0.6                                             PROB                                                                               .279                                                                               .301                                                                               .060*                                                                               .771                                                                               .065*                                                                               .112 .102                                    __________________________________________________________________________                 EST TIL GDU  GDU TST  STA  STK                                             VAR CNT LER SHD  SLK WT   GRN  LDG                                     DEPT    #   ABS ABS ABS  ABS ABS  ABS  ABS                                     __________________________________________________________________________     TOTAL SUM                                                                              1   49.0                                                                               0.3 1535 1620                                                                               51.4 7.8  100.0                                           2   47.9                                                                               10.4                                                                               1555 1620                                                                               51.9 7.2  99.0                                            LOCS                                                                               4   4   2      1 3    4    3                                               REPS                                                                               13  11  3      1 12   10   7                                               DIFF                                                                               1.1 10.1                                                                               20    00 1.4  0.5  1.0                                             PROB                                                                               .307                                                                               .320                                                                               .626     .699 .054*                                                                               4.23                                    __________________________________________________________________________

                                      TABLE 3C                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMK0                                                             VARIETY #2 - PHW79                                                             * = 10% SIG + = 5% SIG # = 1% SIG                                              __________________________________________________________________________                 BU  BU  YLD         EAR BAR   PLT EAR  SDG   EST                           VAR ACR ACR SC    MST   SZ  PLT   HT  HT   VGR   CNT                   DEPT    #   ABS % MN                                                                               ABS   ABS   ABS ABS   ABS ABS  ABS   ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1   82.6                                                                               114 5.8   20.6  5.4 93.3  90.6                                                                               35.2 5.3   44.0                          2   87.2                                                                               121 6.9   19.9  6.3 97.5  92.2                                                                               36.2 5.9   42.5                          LOCS                                                                               27  27  15    39    11  32    31  31   28    49                            REPS                                                                               54  54  17    67    11  43    50  50   43    118                           DIFF                                                                               4.6 6   1.1   0.8   0.9 4.2   1.6 1.0  0.7   1.5                           PROB                                                                               .150                                                                               .248                                                                               .016+ .003# .127                                                                               .035+ .150                                                                               .219 .018+ .005#                 __________________________________________________________________________                 DRP  TIL GDU   GDU   POL POL  POL TAS   TEX  TST                           VAR EAR  LER SHD   SLK   WT  WT   SC  SZ    EAR  WT                    DEPT    #   ABS  ABS ABS   ABS   ABS % MN ABS ABS   ABS  ABS                   __________________________________________________________________________     TOTAL SUM                                                                              1   100.0                                                                               1.4 1561  1625  127.4                                                                              88   5.8 4.8   5.0  55.2                          2   100.0                                                                               0.7 1508  1551  155.7                                                                              108  6.2 6.6   5.8  57.1                          LOCS                                                                               1    23  34    34    4   4    11  18    9    28                            REPS                                                                               2    36  44    45    8   8    18  21    9    56                            DIFF                                                                               0.0  0.6 53    74    28.3                                                                               20   0.4 1.8   0.8  1.9                           PROB     .403                                                                               .000# .000# .112                                                                               .123 .472                                                                               .000# .325 .000#                 __________________________________________________________________________                 GRN   SCT  STA   STK RT   EAR NLF  STW   ECB  ECB                          VAR APP   GRN  GRN   LDG LDG  MLD BLT  WLT   1LF  2SC                  DEPT    #   ABS   ABS  ABS   ABS ABS  ABS ABS  ABS   ABS  ABS                  __________________________________________________________________________     TOTAL SUM                                                                              1   6.1   5.3  5.7   92.3                                                                               98.8 7.9 5.9  8.0   4.4  3.7                          2   7.0   6.0  6.8   93.4                                                                               94.5 7.4 5.1  8.0   5.3  5.3                          LOCS                                                                               12    15   30    16  7    7   8    4     6    2                            REPS                                                                               24    17   48    31  12   9   13   4     8    5                            DIFF                                                                               0.9   0.7  1.1   1.1 4.3  0.4 0.8  0.0   0.8  1.6                          PROB                                                                               .046+ .278 .024+ .425                                                                               .127 .617                                                                               .149 .000# .383 .586                 __________________________________________________________________________

                                      TABLE 3D                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMK0                                                             VARIETY #2 - PHW52                                                             __________________________________________________________________________              BU  BU  YLD    EAR                                                                               BAR                                                                               PLT EAR SDG EST DRP                                                                               TIL                                                                               GDU GDU POL                     VAR ACR ACR SC MST SZ PLT                                                                               HT  HT  VGR CNT EAR                                                                               LER                                                                               SHD SLK SC                 DEPT #   ABS % MN                                                                               ABS                                                                               ABS ABS                                                                               ABS                                                                               ABS ABS ABS ABS ABS                                                                               ABS                                                                               ABS ABS ABS                __________________________________________________________________________     TOTAL                                                                               1   84.4                                                                               113 5.6                                                                               23.7                                                                               5.5                                                                               88.7                                                                              89.0                                                                               36.9                                                                               5.2 37.4                                                                               99.5                                                                              0.7                                                                               1557                                                                               1619                                                                               5.7                SUM  2   74.6                                                                               97  6.2                                                                               20.6                                                                               5.6                                                                               91.2                                                                              76.2                                                                               26.3                                                                               4.6 35.5                                                                               100.0                                                                             1.2                                                                               1463                                                                               1513                                                                               6.2                     LOCS                                                                               29  29  23 45  21 52 57  57  56  86  2  47 58  55  18                      REPS                                                                               76  76  25 97  21 75 90  91  79  170 4  67 68  62  21                      DIFF                                                                               9.8 16  0.6                                                                               3.1 0.0                                                                               2.5                                                                               12.8                                                                               10.6                                                                               0.6 1.9 0.5                                                                               0.5                                                                               94  106 0.5                     PROB                                                                               .013+                                                                              .025+                                                                              .255                                                                              .000#                                                                              .917                                                                              .350                                                                              .000#                                                                              .000#                                                                              .008#                                                                              .039+                                                                              .500                                                                              .266                                                                              .000#                                                                              .000#                                                                              .084*              __________________________________________________________________________              TAS TEX TST GRN SCT STA  STK RT  EAR NLF STW ECB ECB                       VAR SZ  EAR WT  APP GRN GRN  LDG LDG MLD BLT WLT 1LF 2SC                  DEPT #   ABS ABS ABS ABS ABS ABS  ABS ABS ABS ABS ABS ABS ABS                  __________________________________________________________________________     TOTAL                                                                               1   4.8 4.5 54.9                                                                               6.7 5.4 6.2  93.8                                                                               98.5                                                                               7.2 5.8 8.0 5.4 6.8                  SUM  2   5.8 5.8 57.9                                                                               6.8 6.7 5.2  87.8                                                                               92.1                                                                               7.3 3.6 4.7 3.1 3.6                       LOCS                                                                               30  16  30  12  25  41   21  9   18  12  6   17  5                         REPS                                                                               34  16  76  23  27  66   48  14  20  17  6   17  6                         DIFF                                                                               0.9 1.3 3.0 0.1 1.3 0.9  6.0 6.5 0.1 2.1 3.3 2.3 3.2                       PROB                                                                               .002#                                                                              .003#                                                                              .000#                                                                              .870                                                                               .002#                                                                              .025+                                                                               .101                                                                               1.85                                                                               .819                                                                               .000#                                                                              .006#                                                                              .000#                                                                              .016+                __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 3E                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMK0                                                             VARIETY #2 - PHP38                                                             __________________________________________________________________________              BU  BU  YLD    EAR                                                                               BAR                                                                               PLT EAR SDG EST DRP                                                                               TIL                                                                               GDU GDU POL                     VAR ACR ACR SC MST SZ PLT                                                                               HT  HT  GFR CNT EAR                                                                               LER                                                                               SHD SLK SC                 DEPT #   ABS % MN                                                                               ABS                                                                               ABS ABS                                                                               ABS                                                                               ABS ABS ABS ABS ABS                                                                               ABS                                                                               ABS ABS ABS                __________________________________________________________________________     TOTAL                                                                               1   81.6                                                                               114 5.6                                                                               23.9                                                                               5.5                                                                               87.6                                                                              87.9                                                                               36.7                                                                               5.1 35.1                                                                               99.5                                                                              0.7                                                                               1558                                                                               1619                                                                               5.7                SUM  2   66.9                                                                               92  5.3                                                                               18.9                                                                               5.2                                                                               89.2                                                                              81.3                                                                               29.5                                                                               6.1 32.8                                                                               100.0                                                                             1.4                                                                               1452                                                                               1477                                                                               5.0                     LOCS                                                                               19  19  23 32  20 44 51  51  49  78  2  42 57  55  18                      REPS                                                                               38  38  25 56  20 52 69  69  59  141 4  52 64  62  21                      DIFF                                                                               14.8                                                                               22  0.3                                                                               6.1 0.3                                                                               1.5                                                                               6.6 7.2 1.0 2.4 0.5                                                                               0.7                                                                               106 142 0.7                     PROB                                                                               .011+                                                                              .023+                                                                              .522                                                                              .000#                                                                              .358                                                                              .586                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .500                                                                              .206                                                                              .000#                                                                              .000#                                                                              .048+              __________________________________________________________________________              TAS TEX TST GRN SCT STA  STK RT  EAR NLF STW ECB ECB                       VAR SZ  EAR WT  APP GRN GRN  LDG LDG MLD BLT WLT 1LF 2SC                  DEPT #   ABS ABS ABS ABS ABS ABS  ABS ABS ABS ABS ABS ABS ABS                  __________________________________________________________________________     TOTAL                                                                               1   4.8 4.5 55.3                                                                               6.3 5.5 5.8  90.1                                                                               98.0                                                                               7.2 5.8 8.0 5.4 6.8                  SUM  2   5.2 6.6 59.4                                                                               7.3 6.1 5.3  86.2                                                                               97.1                                                                               7.7 3.8 3.7 3.3 4.4                       LOCS                                                                               30  16  20  10  24  31   12  6   18  12  6   17  5                         REPS                                                                               34  16  40  19  26  42   23  9   20  17  6   17  6                         DIFF                                                                               0.3 2.1 4.1 0.9 0.7 0.5  3.9 0.9 0.6 2.0 4.3 2.1 2.4                       PROB                                                                               .257                                                                               .000#                                                                              .000#                                                                              .118                                                                               .141                                                                               .304 .194                                                                               .638                                                                               .145                                                                               .000#                                                                              .000#                                                                              .000#                                                                              .070*                __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 3F                                     __________________________________________________________________________     PAIRED INBRED COMPARISON DATA                                                  VARIETY #1 - PHMK0                                                             VARIETY #2 - PHP85                                                             __________________________________________________________________________              BU  BU  YLD    EAR                                                                               BAR                                                                               PLT EAR SDG EST DRP                                                                               TIL                                                                               GDU GDU POL                     VAR ACR ACR SC MST SZ PLT                                                                               HT  HT  GFR CNT EAR                                                                               LER                                                                               SHD SLK SC                 DEPT #   ABS % MN                                                                               ABS                                                                               ABS ABS                                                                               ABS                                                                               ABS ABS ABS ABS ABS                                                                               ABS                                                                               ABS ABS ABS                __________________________________________________________________________     TOTAL                                                                               1   73.8                                                                               91  5.6                                                                               26.5                                                                               5.5                                                                               86.5                                                                              88.3                                                                               36.7                                                                               5.0 29.6                                                                               99.1                                                                              0.7                                                                               1559                                                                               1619                                                                               5.7                SUM  2   99.4                                                                               139 6.5                                                                               22.2                                                                               5.5                                                                               93.8                                                                              84.5                                                                               30.6                                                                               5.9 27.9                                                                               100.0                                                                             1.4                                                                               1468                                                                               1511                                                                               4.8                     LOCS                                                                               7   7   23 15  21 34 41  41  42  62  1  39 56  54  18                      REPS                                                                               14  14  25 25  21 38 52  52  45  113 2  46 63  60  21                      DIFF                                                                               25.5                                                                               48  0.9                                                                               4.3 0.0                                                                               7.2                                                                               3.8 6.1 0.8 1.7 0.9                                                                               0.7                                                                               91  108 0.9                     PROB                                                                               .022+                                                                              .048+                                                                              .050*                                                                             .001#                                                                              .000#                                                                             .039+                                                                             .001#                                                                              .000#                                                                              .002#                                                                              .001#  .030+                                                                             .000#                                                                              .000#                                                                              .022+              __________________________________________________________________________              TAS TEX TST GRN SCT STA  STK RT  EAR NLF STW ECB ECB                       VAR SZ  EAR WT  APP GRN GRN  LDG LDG MLD BLT WLT 1LF 2SC                  DEPT #   ABS ABS ABS ABS ABS ABS  ABS ABS ABS ABS ABS ABS ABS                  __________________________________________________________________________     TOTAL                                                                               1   4.8 4.5 53.4                                                                               6.2 5.5 6.5  95.2                                                                               98.2                                                                               7.3 5.7 8.0 5.4 6.8                  SUM  2   4.3 5.1 56.0                                                                               6.7 7.1 6.4  89.9                                                                               94.2                                                                               7.5 2.9 5.7 3.5 4.3                       LOCS                                                                               30  16  8   6   24  24   8   3   17  10  6   17  5                         REPS                                                                               34  16  16  11  26  28   15  3   19  13  6   17  6                         DIFF                                                                               0.6 0.6 2.5 0.5 1.6 0.0  5.3 4.0 0.2 2.8 2.3 1.8 2.5                       PROB                                                                               .062*                                                                              .136                                                                               .001#                                                                              .497                                                                               .001#                                                                              .949 .286                                                                               .615                                                                               .699                                                                               .000#                                                                              .005#                                                                              .001#                                                                              .024+                __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 4A                                     __________________________________________________________________________     AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHMK0 TO PHW52 CROSS-           ED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME EXPERIMENTS.               ALL VALUES ARE EXPRESSED AS PERCENT OF THE EXPERIMENT MEAN EXCEPT              PREDICTED RM, SELECTION INDEX, AND YIELD (BU/ACR).                             __________________________________________________________________________                      SEL                                                                               BU       GDU PRM STK RT  STA                                            PRM IND                                                                               ACR                                                                               YLD                                                                               MST                                                                               SHD SHD LDG LDG GRN                               __________________________________________________________________________     TOTAL  REPLIC.                                                                              162 161                                                                               161                                                                               161                                                                               162                                                                               46  9   115 46  95                                MEAN WTS                                                                              PHMK0 120 100                                                                               181                                                                               102                                                                               107                                                                               104 119 100 88  118                               MEAN WTS                                                                              PHW52 118 111                                                                               192                                                                               109                                                                               103                                                                               100 116 101 108 110                                      DIFF. 2   12 11 7  4  3   3   1   21  8                                 __________________________________________________________________________                   TST  GRN SDG  EST                                                                               STK PLT                                                                               EAR DRP                                                                               BRT                                             WTA  APP VGR  CNT                                                                               CNT HT HT  EAR                                                                               STK                               __________________________________________________________________________     TOTAL   REPLIC.                                                                              156  18  90   112                                                                               166 96 98  6  5                                 MEAN WTS                                                                               PHMK0 98   79  90   101                                                                               99  104                                                                               105 100                                                                               97                                MEAN WTS                                                                               PHW52 100  100 113  101                                                                               101 100                                                                               99  100                                                                               101                                       DIFF. 2    21  23   0  1   4  6      3                                 __________________________________________________________________________

                                      TABLE 4B                                     __________________________________________________________________________     AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHMK0 TO PHP38 CROSS-           ED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME EXPERIMENTS. ALL           VALUES ARE EXPRESSED AS PERCENT OF THE EXPERIMENT MEAN EXCEPT                  PREDICTED RM, SELECTION INDEX, AND YIELD (BU/ACR).                             __________________________________________________________________________                      SEL                                                                               BU       GDU PRM STK RT  STA                                            PRM IND                                                                               ACR                                                                               YLD                                                                               MST                                                                               SHD SHD LDG LDG GRN                               __________________________________________________________________________     TOTAL  REPLIC.                                                                              77  76 76 76 77 25  7   58  13  45                                MEAN WTS                                                                              PHMK0 117 97 185                                                                               98 104                                                                               102 117 101 88  115                               MEAN WTS                                                                              PHW38 113 103                                                                               190                                                                               102                                                                               94 98  114 101 101 84                                       DIFF. 4   6  6  3  10 4   4   0   13  31                                __________________________________________________________________________                            TST SDG EST                                                                               STK                                                                               PLT                                                                               EAR                                                                               DRP                                                                               BRT                                                     WTA VGR CNT                                                                               CNT                                                                               HT HT EAR                                                                               STK                              __________________________________________________________________________               TOTAL  REPLIC.                                                                              70  58  65 77 39 39 8  5                                          MEAN WTS                                                                              PHMK0 99  84  100                                                                               100                                                                               101                                                                               103                                                                               100                                                                               96                                         MEAN WTS                                                                              PHW52 100 106 99 100                                                                               99 98 100                                                                               105                                               DIFF. 1   23  2  0  2  5     9                                __________________________________________________________________________

                                      TABLE 4C                                     __________________________________________________________________________     AVERAGE INBRED BY TESTER PERFORMANCE COMPARING PHMK0 TO PHP85 CROSS-           ED TO THE SAME INBRED TESTERS AND GROWN IN THE SAME EXPERIMENTS. ALL           VALUES ARE EXPRESSED AS PERCENT OF THE EXPERIMENT MEAN EXCEPT                  PREDICTED RM, SELECTION INDEX, AND YIELD (BU/ACR).                             __________________________________________________________________________                      SEL                                                                               BU       GDU PRM STK RT  STA                                            PRM IND                                                                               ACR                                                                               YLD                                                                               MST                                                                               SHD SHD LDG LDG GRN                               __________________________________________________________________________     TOTAL  REPLIC.                                                                              83  82 82 82 83 29  6   70  21  40                                MEAN WTS                                                                              PHMK0 117 101                                                                               193                                                                               100                                                                               103                                                                               103 117 100 93  108                               MEAN WTS                                                                              PHW85 115 103                                                                               197                                                                               102                                                                               98 99  115 98  94  85                                       DIFF. 2   2  4  2  5  3   3   2   1   23                                __________________________________________________________________________                   TST  GRN SDG  EST                                                                               STK PLT                                                                               EAR DRP                                                                               BRT                                             WTA  APP VGR  CNT                                                                               CNT HT HT  EAR                                                                               STK                               __________________________________________________________________________     TOTAL   REPLIC.                                                                              75   7   50   57 88  53 53  11 9                                 MEAN WTS                                                                               PHMK0 99   103 85   100                                                                               100 105                                                                               106 100                                                                               100                               MEAN WTS                                                                               PHW85 99   99  111  100                                                                               99  102                                                                               99  100                                                                               104                                       DIFF. 0    4   26   1  1   4  7   0  4                                 __________________________________________________________________________

                                      TABLE 5A                                     __________________________________________________________________________     VARIETY #1 - PHMK0 HYBRID                                                      VARIETY #2 - PHW52 HYBRID                                                      __________________________________________________________________________                         BU  BU      STK RT  STA TST                                        VAR     PRM ACR ACR MST LDG LDG GRN WTA                                DEPT    #   PRM SHD ABS % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                               __________________________________________________________________________     TOTAL SUM                                                                              1   117 118 175.9                                                                              102 107 100 96  109 101                                        2   115 115 178.2                                                                              103 99  97  109 92  102                                        LOCS                                                                               83  32  341 341 345 254 118 209 328                                        REPS                                                                               83  32  555 555 561 406 203 344 533                                        DIFF                                                                               3   3   2.4 2   8   2   14  17  1                                          PROB                                                                               .000#                                                                              .000#                                                                              .058*                                                                              .034+                                                                              .000#                                                                              .014+                                                                              .000#                                                                              .000#                                                                              .000#                              __________________________________________________________________________                 GRN SDG EST STK PLT EAR DRP BRT GDU                                        VAR APP VGR CNT CNT HT  HT  EAR STK SHD                                        #   % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                               __________________________________________________________________________     TOTAL SUM                                                                              1   100 78  101 100 108 110 100 102 105                                        2   103 99  98  100 100 94  100 99  101                                        LOCS                                                                               107 155 198 360 157 162 70  23  85                                         REPS                                                                               188 262 320 586 242 252 101 44  130                                        DIFF                                                                               3   21  3   0   8   16  0   3   4                                          PROB                                                                               .030+                                                                              .000#                                                                              .000#                                                                              .997                                                                               .000#                                                                              .000#                                                                              .946                                                                               .083*                                                                              .000#                              __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

                                      TABLE 5B                                     __________________________________________________________________________     VARIETY #1 - PHMK0 HYBRID                                                      VARIETY #2 - PHW52 HYBRID                                                      __________________________________________________________________________                         BU  BU      STK RT  STA TST                                        VAR     PRM ACR ACR MST LDG LDG GRN WTA                                DEPT    #   PRM SHD ABS % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                               __________________________________________________________________________     TOTAL SUM                                                                              1   123 121 169.6                                                                              101 114 100 80  139 97                                         2   120 118 186.2                                                                              111 108 102 100 129 100                                        LOCS                                                                               9   4   49  49  50  38  9   26  48                                         REPS                                                                               9   4   69  69  71  54  11  38  69                                         DIFF                                                                               3   3   16.5                                                                               10  6   2   20  10  2                                          PROB                                                                               .026+                                                                              .166                                                                               .000#                                                                              .000#                                                                              .000#                                                                              .488                                                                               .046+                                                                              .203                                                                               .000#                              __________________________________________________________________________                 GRN SDG EST STK PLT EAR DRP BRT GDU                                        VAR APP VGR CNT CNT HT  HT  EAR STK SHD                                        #   % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                                                                               % MN                               __________________________________________________________________________     TOTAL SUM                                                                              1   82  92  101 98  105 107 100     106                                        2   97  112 102 101 100 102 100     102                                        LOCS                                                                               10  26  32  54  26  27  3       14                                         REPS                                                                               19  39  46  75  37  39  6       23                                         DIFF                                                                               15  19  1   3   5   5   0       4                                          PROB                                                                               .060*                                                                              .004#                                                                              .479                                                                               .029+                                                                              .000#                                                                              .023+                                                                              1.00    .000#                              __________________________________________________________________________      * = 10% SIG                                                                    + = 5% SIG                                                                     # = 1% SIG                                                               

INDUSTRIAL APPLICABILITY

The foregoing is set forth by way of example and is not intended to limit the scope of the invention.

This invention also is directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant wherein the first or second parent corn plant is an inbred corn plant from the line PHMK0. Further, both first and second parent corn plants can come from the inbred corn line PHMK0. Thus, any such methods using the inbred corn line PHMK0 are part of this invention: selfing, backcrosses, hybrid production, crosses to populations, and the like. It also would include more unconventional methods of combining the inbred with another such as using various culturing techniques known to those skilled in the art. All plants produced using inbred corn line PHMK0 as a parent are within the scope of this invention. Advantageously, the inbred corn line is used in crosses with other, different, corn inbreds to produce first generation (F₁) corn hybrid seeds and plants with superior characteristics.

As used herein, the term plant includes plant cells, plant protoplasts, plant cell tissue cultures from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as embryos, pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk and the like.

Duncan, Williams, Zehr, and Widholm, Planta, (1985) 165:322-332 reflects that 97% of the plants cultured which produced callus were capable of plant regeneration. Subsequent experiments with both inbreds and hybrids produced 91% regenerable callus which produced plants. In a further study in 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988), 7:262-265 reports several media additions which enhance regenerability of callus of two inbred lines. Other published reports also indicated that "nontraditional" tissues are capable of producing somatic embryogenesis and plant regeneration. K. P. Rao, et al., Maize Genetics Cooperation Newsletter, 60:64-65 (1986), refers to somatic embryogenesis from glume callus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347 (1987) indicates somatic embryogenesis from the tissue cultures of maize leaf segments. Thus, it is clear from the literature that the state of the art is such that these methods of obtaining plants are, and were, "conventional" in the sense that they are routinely used and have a very high rate of success.

Tissue culture of corn is described in European Patent Application, publication 160,390, incorporated herein by reference. Corn tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize",Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Virginia 1982, at 367-372) and in Duncan, et al., "The Production of Callus Capable of Plant Regeneration from Immature Embryos of Numerous Zea Mays Genotypes," 165 Planta 322-332 (1985). Thus, another aspect of this invention is to provide cells which upon growth and differentiation produce corn plants having the physiological and morphological characteristics of the inbred line PHMK0.

Corn is used as human food, livestock feed, and as raw material in industry. The food uses of corn, in addition to human consumption of corn kernels, include both products of dry- and wet-milling industries. The principal products of corn dry milling are grits, meal and flour. The corn wet-milling industry can provide corn starch, corn syrups, and dextrose for food use. Corn oil is recovered from corn germ, which is a by-product of both dry- and wet-milling industries.

Corn, including both grain and non-grain portions of the plant, is also used extensively as livestock feed, primarily for beef cattle, dairy cattle, hogs, and poultry.

Industrial uses of corn are mainly from corn starch in the wet-milling industry and corn flour in the dry-milling industry. The industrial applications of corn starch and flour are based on functional properties, such as viscosity, film formation, adhesive properties, and ability to suspend particles. The corn starch and flour have application in the paper and textile industries. Other industrial uses include applications in adhesives, building materials, foundry binders, laundry starches, explosives, oil-well muds, and other mining applications.

Plant parts other than the grain of corn are also used in industry. Stalks and husks are made into paper and wallboard and cobs are used for fuel and to make charcoal.

The seed of inbred corn line PHMK0, the plant produced from the inbred seed, the hybrid corn plant produced from the crossing of the inbred, hybrid seed, and various parts of the hybrid corn plant can be utilized for human food, livestock feed, and as a raw material in industry.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims.

DEPOSITS

Applicants have made available to the public without restriction a deposit of at least 2,500 seeds of Inbred Corn Line PHMK0 with the American Type Culture (ATCC), Rockville, Maryland 20853 USA, ATCC Deposit No. 75693. The seeds deposited with the ATCC are taken from the same deposit maintained by Pioneer Hi-Bred International, Inc., 700 Capital Square, 400 Locust Street, Des Moines, Ia. 50309 since prior to the filing date of this application. This deposit of the Inbred Corn Line PHMK0 will be maintained without restriction in the ATCC depository, which is a public depository, for a period of 30 years, or 5 after the most recent request, or for the effective life of the patent, whichever is longer, and will be replaced if it becomes nonviable during that period. 

What is claimed is:
 1. Inbred corn seed designated PHMK0 and having ATCC Accession No.
 75693. 2. A corn plant produced by the seed of claim
 1. 3. A tissue culture of regenerable cells of a PHMK0 wherein the tissue regenerates plants having the genotype of PHMK0.
 4. A tissue culture according to claim 3, the tissue selected culture selected from the group consisting of leaves, pollen, embyros, roots, root tips, anthers, silk, flowers, kernels, ears, cobs, husks and stalks and cells and protoplasts thereof.
 5. A corn plant having the genotype of PHMK0 regenerated from the tissue culture of claim
 3. 6. Hybrid seed produced by:(a) planting, in pollinating proximity, seeds of corn inbred lines PHMK0 and another inbred line; (b) cultivating corn plants resulting from said planting; (c) preventing pollen production by the plants of one of the inbred lines; (d) allowing natural cross pollinating to occur between said inbred lines; and (e) harvesting seeds produced on plants of the inbred line of step (c).
 7. Hybrid seed produced by hybrid combination of plants of inbred corn seed designated PHMK0 and having ATCC Accession No. and plants of another inbred line.
 8. Hybrid plants grown from seed of claim
 7. 9. A tissue culture of the regenerable cells of the corn plant of claim
 3. 10. Tissue culture of the regenerable cells of the corn plant of claim
 8. 11. A first generation (F₁) hybrid corn plant produced by the process of:(a) planting, in pollinating proximity, seeds of corn inbred lines PHMK0 and another inbred line; (b) cultivating corn plants resulting from said planting; (c) preventing pollen production by the plants of one of the inbred lines; (d) allowing natural cross pollinating to occur between said inbred lines; (e) harvesting seeds produced on plants of the inbred line of step (c); and (f) growing a harvested seed of step (e). 